If you did not drive in to Puerto Peñasco as most visitors do you can get around town via taxi. You can either have the hotel call them for you or go to the nearest major street and flag one down, fares vary however you should not pay more than $2 or $3 dollars per person, in the touristic area of Sandy Beach you will find the "taxi turistico" or "tourist taxi" their prices will be higher than those of regular taxis.
There are also microbuses that take people around town mostly workers for a minimal fee.
If you will be staying for a longer period, there are 2 places that you can rent a car:
The Point Rent-a-car
On Blvd Benito Juarez across from Latitud 31 Restaurant and bar, tel. 388-5823